Pen



FIG. 1 is a right front perspective view of a pen showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof, the right side being amirror image thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

I claim the ornamental design for a pen, as shown and described.